Change the value in a field to another value

You have an entry in a MySQL database that you want to change.
ie, you may want to re-reference an image folder or in my case, archive all the events on a sports site before the new season. To do this you need the following code:

update [table_name] set [field_name] =
replace([field_name],'[string_to_find]','[string_to_replace]');

Example:

UPDATE wp_posts SET post_type = REPLACE(post_type, 'sp_event', '2018-19');